The ongoing parent study, RV 254 (SEARCH 010, WRAIR 1494), enrolls participants with documented acute HIV infection at the Thai Red Cross AIDS Research Center in Bangkok, Thailand. Participants in the cohort are primarily men who have sex with men, but also include men and women with other HIV acquisition risk factors as well as various ages, incomes, and education levels. All participants in RV 254 are offered ART at the time of enrollment through a separately funded protocol. Participants in this substudy will remain co-enrolled in RV254/SEARCH010, but will follow the schedule of event (SOE) for this sub-study in lieu of the parent study SOE.